Method of making athletic balls



Nov. 12, 1940. w. J. VOlT ET AL 2,221,534

METHOD OF MAKING ATHLETIC BALLS Original Filed Nov. 6, 1937 2 Sheets-Sheet l lNl/i/VTORS W/LL/AM d. Mar 1.5m; C. WE/MEI? HAARL'aj/(ILCMFOSTLR 8: HARE/.5

FOR THE FIRM A TTOANE KS.

Nov.412 1940. V w, J, .vo 2,221,534

METHOD OF MAKING ATHLETIC BALLS Original Filed Nov. 6, 1937 2 Sheets-Sheet 2 HAR/PLZ/(IECH, Fosrae 6 HA/PR/s FOR THE FIRM Patented Nov. 12, 11940 UNITED STATES PATENT OFFICE nmrnon or mama ATHLETIC mus William J. Voit, Lu Angels, and Leith c. Weimer,

Southgate Volt can; add Welmel' asaignor to said cation November 6, 1937, Serial No.

vllled and this application April 19, 1939, Serial N04 288.682

: Claims. (cl. 154- 16) prevent the ball from being deformed by heavy This application is a division of our application Serial No. 173,158, for an Athletic ball.

This invention relates to a method of making inflatable athletic balls.

It relates particularly to a method of making that class of inflatable athletic balls which comprise a central bladder to provide a means of innation, an intermediate wall of relatively nonstretchable material, to give the ball a definite or other materials, but provides a water-proof casing for the ball, which prevents the entrance of water, dirt and other deleterious matter into the substance of the intermediate layer, where such foreign matter would cause decay and mechanical destruction, with resultant disintegration of the material of this intermediate layer.

One of the objects of our invention is to provide a method of making athletic balls of this type, which shall be rapid in operation, economical of the time of the factory operatives, and shall re-= quire a minimum of mechanical equipment.

In these athletic balls it is desirable to provide an intermediate relatively non-stretchable wall which shall be composed of a plurality of segments, facilitating accurate conformation of the wall to the central bladder, which segments shall be firmly united into'one continuous wall capable of transmitting stresses in every direction throughout its entire extent.

Anotherobject of our invention is to thus firmly unite these segments by the use" of marginal seams, and to so dispose these seams that they will not cause the ball to have uneven elasticity, will not deform the outer surface of the ball with ridges or other objectionable deviations from true shape, and will act to prevent relative circumferential displacement of the outer cover and intermediate layer.

Another object of our invention is to provide a method of making a ball of this type, in which the intermediate layer is so fabricated that it will almost completely resist stretching stresses. When the ball is inflated, the intermediate fabric layer will, because of this resistance to stretching stresses, prevent the ball from becoming larger than the size established by the regulations of the game for which the ball is designed. And this same resistance to stretching stresses will blows against floor. walls, or other objects, and will lengthen its life. Another object of our invention is to provide a method out-making a ball which shall be readily inflatable, will not stretch, will resist surface wear, be water-proof, andhave no surface seams, ridges or irregularities, and which shall in combination with these several attributes, be characterized by a continuous, integral webwork of,

vulcanized rubber from innersurface to outer surface, binding the entire structure together in a flexible whole, but yet in such a manner as to prevent relative movement of its component parts, and the resulting "breakdown of the walls of the ball which occurs when adjoining particles begin such a relative movement. Another object is to provide a method of making balls of this type, which makes possible a rapid and workmanlike application of the segments of a one-piece rubber cover to the inter mediate fabric layer prior to molding the cover on the ball which object is attained by providing a fabric layer with a smooth surface without ridges or other elevations. Other features and advantages of our invention will appear from a reading of the specification and drawings, and will be presented in the claims.

, In the drawings: 1

Fig. 1 is a fragmentary elevational view, partly in section of the central bladder.

Fig. 2 is an elevational view of the partly finished ball, showing the manner of applying the,

fabric segments of the intermediate wall, with some of the segments broken away to more clearly disclose the construction.

Fig. 3 is a perspective view of the partly finished ball, showing it at the same stagemf con struction as that of Fig. 2, and also with some .of the segments of the/intermediate wall broken away. I

r Fig. 4 is a fragmentary sectional view of the partly finished ball of Figs. 2 and 3 and the mold in which it has been placed, and before the application ofinternal pressure.

Fig. 5 is a showing similar to that of Fig. 4, but after the application of internal pressure.

Fig. 6 is an elevational view showing the method of applying the segments of the outer rubber cover to the partly finished ball, some of the segments being broken away to more clearly disclose the construction.

Fig. 7 is a fragmentary sectional view of the ball with the segments of the rubber cover in place, and with the ball in position in a second mold, but prior to the application of internal pressure.

Fig. 8 is a showing similar to that of Fig. 7, but after the application of internal pressure.

Fig. 9 is a fragmentary elevational view of the completed ball, partly in section.

Fig. 10 is an elevational view'of a partly finished ball, shown partly in section, illustrating the use of alcohol as a forming filler for the bladder during the manufacturing process.

Fig. 11 is a sectional elevational view of the partly finished ball of Fig. 10 after being placed in a mold.

For reference purposes it is convenient to speak of the poles and the equatorial region of the athletic ball. drawings, except Fig. 3, the polar axis of the ball is a horizontal line perpendicular to the plane of the drawing sheet, and the equatorial line appears as a bounding, great circle or an arc of a great circle, according to whether the view is complete or fragmentary.

In Fig. 3 one of the poles is shown near the top While the ball depicted in the drawings is spherical, our invention is equally applicable to athletic .balls which are either elliptical in longitudinal cross section, or of some other shape suitable to the purpose for which they are designed. Whenever words applicable to a'spherical ball appear in this description, it will be understood that it is for convenience of description only, and that corresponding words applicable to some other shape may be substi- -tuted throughout. i

We first make in accordance with standard methods a thin walled rubber bladder ll having a shape when inflated like that of the finished ball, and provide it with an air check valve l2- of the :type usually used for this purpose. Throughthis valve we then admit air or any other suitable gas under pressure, and inflate the bladder until it reaches a size slightly less than that desired for the completed ball. The bladder is next completely coated with a rubber'cement l3 by dipping the bladder in a bath of the cementor in any other suitable manner. Pieces or segments H of relatively non-stretchable rubberized fabric, commonly known as friction fabric are then applied to the cement coated bladder to form a continuous and complete layer or'wal1 I6 on the exterior surface of the bladder. These pieces of fabric may be cut and applied in any one of a number of ways to present any one of a number of different patterns. And they may be applied in one or more thicknesses, as may be required to meet the conditions of any particular problem of ball design. But whatever the pattern of application or the number of thicknesses, we have found it preferable to give the several pieces a shape and size such that their meeting edges overlapto form thickened seams i5. 1 The underface of the overlapping edge of one piece is preferably treated with rubber cement to cause it to adhere to the outer surface of the edge of the adjacent piece beneath it. When. the pieces or segments, to complete one thickness of the fabric wall, have been applied theball is again givena coating of rubber cement, and the pieces constituting the next thickness placed in position.

Figs. 2 and 3 illustrate a preferred construction of the wall l6. Three thicknesses are shown, each comprising a circular polar piece or segment I1, and longitudinal segments l8. Each of these longitudinal segments overlaps correspond- In all of the figures of the inner surface 29 .of the bladder.

ing polar pieces I! atits two ends, respectively, and each longitudinal segment overlaps along one of its longitudinal edges, the next adjacent longitudinal segment, to form a seam 15. When the layer is made up of more than one thickness, we preferably extend the overlapping end IQ of each longitudinal segment beyond the circular edge 20 of its corresponding polar cap segment i! to form a butt joint at 2| with-the circular edge 22 of the next outer polar cap segment [1a. The polar edges 23 of the outermost layer of longitudinal fabric segments may be for ease of manufacture disposed 'a short distance away from the pole of the ball, and the small circle bounded by these edges may be left un-' filled by any fabric segment. That longitudinal segment or segments which are applied over the end 24 of the valve [2 are each provided with a small aperture 25 registering with the "valve in the bladder.

After the one or more layers of rubberized fabric constituting the wall i6 have been placed in position upon the bladder, the ball with outwardly projecting seams I5, is put in a mold 26 of spherical shape, and of which the size is slightly less than that of thefinished ball. As will be seen from an inspection of Fig. 4 of the drawings, the inner'face of the mold is spaced from those portions of the outer surface of the outer layer of segments [8 which are between the seams l5. Air or other gas is then forced through the valve l2 into the interior chamber 21 of the bladder H, and a pressure applied sufficient to force the wall H5 at all, points of its outer surface into intimate contact with the inner face 28 ofthe mold. In practice it has been found that a pressure of approximately ninety pounds per square inch is required for this purpose. the wall l6 between the seams I5 are raised until flush with the outermost portions of the seams, whch thus disappear as features of the outer surface of the wall [6. At the same time, as shown in Fig. 5, ribs or seams 30 appear on the At this juncture sufficient heat is applied to the mold, and for a sufiicient time, to'partially vulcanize the rubber component of the fabric segments I4 and the rubber cement used in assembling these segments. This heat partially hardens the rubber and fixes in rigid position the ribs 30 which project inwardly of the bladder wall.

The ball is then deflated and removed from the mold; While we prefer at this stage to apply a protective cover of rubber or other material, the process of manufacture as so far described may be employed to produce a completed ball, in which case the wall l6 becomes the outer wall of the ball. For some types of use and if the wall I6 is made of proper materials, an athletic ball without an additional protective wall may give satisfactory performance.

When the ball is to be provided with a rubber cover, it is, after removal from the mold 26 reinflated, sufficiently to give it that degree of rigidity desirable for the next step in the process of manufacture. This step consists of the application of pieces or segments 3| of unvulca-nized rubben We prefer to out six longitudinal segments 3i and one circular polar segment Bio. The ball is first coated with rubber cement, by dipping or otherwise, and the segments 31, Ma applied andfitted upon the outer surface of the wall It. The segments are so designed and cut that they fit together with butt joints to completely cover the wall I in one continuous rubber layer or wall 32. Fig. '6 shows the pattern according to which we prefer to apply these. segments 3i and ila.

The ball is then placed in the secondmold II, as shown in Fig. '7. This mold is, like mold 26, of the shape of the finished ball, and is also of thesame size as that of the flnished ball. As will be seen from aninspection of Fig. 7 of the drawings, the inner face of the mold is spaced from the outer surface of the wall 31. Air or other gas is then forced through the valve I into the interior chamber '21 of the bladder II, and a pressure applied suflicient toforce the wall 32 at all points of its outer surface into intimate contact with theinner face "of the mold. At the same time the intermediate wall II and the bladder H are pressed outwardly, the wall it against the rubber wall 32, and the bladder against the wall I. The wall i6 as it moves outwardly isstretched. when a sheet of rubberized fabric, such as that used inmaking'the wall it, is stretched by tensile stresses applied longitudinally of the sheet, seam ridges, such as those at 30. tend to disappear and corresponding seam ridges tend to appear on the opposite face of the sheet. In accordance with this principle, when a pressure of approximately ninety pounds is applied within the ball, when in position in the mold 33, the ridges ll tend to disappear and corresponding ridges 3| appear on the outer surface of wall II. The ridges II are also flattened out, and the ridges ll correspondingly produced on the outer faceof wall ll by the direct effect of pneumatic pressure acting radially outward. Fig. 8 shows the ball after the application of pressure to it in the mold, and in that figure the inner face of the bladder II and wall I. are shown as smooth, and ridges I! areshown projecting outwardly into the material of the rubber cover 82. Heat is then applied to the mold I! to vulcanize the rubber of the bladder, ofthe cement, of ,the fabric wall ii, and of the rubber cover 32, which unites into-one flexible whole,

the several elements of the ball, withtheelements disposed as shown in Fig. 8. The material of the segments of the rubber cover becomes plastic when heated and forms itself'with a smooth exterior surface and an interior surface conforming to the outer surface of the wall ll, and is then hardened in that position. The ridges 35 are fixed in the position they assumed when the ball was subjected to the pressure of inflation, and become permanently embedded in the wall 32 of the rubber cover. After vulcanization is completed the ball is deflated and then removed from the mold 33, completed and ready for use. The inner surface of the mold 33 may be engraved to imitate the grain and seams of the covering of a regulation leather covered football or basketball and the design will then appear on the exterior surface of the ball. Inflatable rubber balls have been heretofore produced with seams and grain imitative of the exterior surface of a leather covered ball, but the walls of these balls have not been provided with a fabric constituent or any other reinforcing means to prevent the stretchmg or other deformation of the outermost rubber layer which isiormed with these imitative marks. As a result, when the ball has become stretched or locally deformed, the imitative marks have been correspondingly distorted, and given an unreal appearance, which destroys the simulation of a leather covered ball.

The ball as completed presents no ridges or seams on its outer surface. The ridges I! embedded in the rubber cover 32 act to key together the two walls I8 and 32, and prevent relative circumferential displacement. That feature of our method of making our athletic ball, by which would be the ease with butt joints; It affords a smooth surface on the unfl'nished ball for the rapid application of the segments of the rubber cover.

The wall I! serves the primary purpose of preventing the walls of the ball from stretching'out of shape or to an undesirable'size. For that reason they are made of fabric material. In our process this fabric material is twice subjected to a heavy internal pressure of inflation which stretches it in advance of the use of theball for play purposes, since the mold used in conjunction with each application of internal pressure is larger than the ball structure placed within it. Each time that it is subjected to this stretching action the'flbers of the material become tensionally deformed and less liable to further elongation when subjected to the stresses arising during the use of the ball. Also at thetime of each stretching; the rubber constituent of the fabric material is given a degree of vulcanization.

which tends/to strengthen the fabric material against further elongation. Figs. 10 and 11 illustrate a modiflcation of our method of making an athletic ball. The bladder was placed in a mold and fllled with an alcohol which has a temperature of liquefaction somewherebetween normal atmospheric temperatures and the temperature of vulcanization. Cetylalcohol, ceryl alcohol, or mericyl alcohol has such a meltin gpoint. An alcohol of this type is melted and iniected into the bladder, while in a mold.

Thealcohol is then cooled until it solidifies, and

. the bladder, now filled with a solid substance, is I removed from the mold. The solid alcohol gives a relatively unyielding form to the bladder upon which the segments of the wall I! can be readily applied. Fig. 10 shows the bladder Ii fllled with solid alcohol 38, and shows the segments ll of the wall Ii applied to the bladder ready to be placed in the flrst vulcanizing mold 20. Fig. 11 shows the unfinished ball in the mold before the application of additional pressure. Heat is now ap-, plied sufficient to melt the alcohol, but not sufficient to vulcanize therubber constituents of the ball. Additional hot liquid alcohol is injected, and the pressure within the bladder raised to approximately ninety pounds. From this point, the process of manufacturing the ball is continued as heretofore described, except that each time deflation or infla ion is required, the temperature of the ball and alcohol must be between the liquefaction point of the alcohol and the vulcanization point of the rubber, and each time wall segments are to be applied, the temperature of the alcohol and ball should be below the liquefaction point'of the alcohol.

Wheretwo successive applications of layers or walls are made to the form, the second high pressure inflationapplied'while the ballis in the second mold can be made by the use of {air or other gas instead of by the injection of additional liquid jalcohol, sincethere is no subsequent step in the process for which a solid form is needed. It is also apparent that two or more outer walls or layers of material can beapplied successively to the solid form without any intermediate step of vulcanization, and all the walls vulcanized upon the form at one operation. The high pressure inflation imparted prior to vulcanization can inthatcase also be effected by the injection of either air. or liquid alcohol. Similarly, when the completed ball is to have but one layer of material, this one layer can be applied to the solid form, and the high pressure applied during the molding operation can be attained by the use of alcohol or air. It is even possible, when two or more layers or walls are applied to the form and each layer is separately subjected to the molding and vulcanizing operation, to use air to effect the high pressure required to force the ball material against-the inner surface of the mold, during the first of such molding and vulcanizing operations,

which comprises two applications of material and two vulcanizing operations, we can vary our method of using the alcohol by removing all the alcohol from the ball after the first vulcanizing operation and relyingsolely on air pressure, subsequently applied, to give the ball the requisite rigidity for the application of the segments of th outermost wall. p

We may omit the use of a central bladder en-' tirely in that modification of our process which involves the use of alcohol to provide a solid form upon which to build up the wall or walls of the ball. In that case, we may form the solid core of alcohol in a suitable mold and rely on the materials in the one or more walls of the ball to .retain the alcohol or both alcohol and air injected into the ball during the manufacturing process. While we have referred to alcohol of the physical qualities above recited as one material which may be used in our modifled method of manufacture, it is obvious that other materials are also adapted to meet the conditions of our process- We can mention as examples of such other materials, parafiine, wax, and ordinary water ice. I

' 'While we have shown and described one particular method of making an athletic ball and several modifications thereof which embody our invention, we do not wish to be limited to the.

particular method and modifications herein .described, but desire to include in the scope of our invention the features of novelty substantially as set. forth in the following claims.

We claim as our invention: 1. A method of making an.inflatable athletic ball, comprising: forming an inflatable rubber ball of smooth contour; applying an outer layer thereto comprising some vulcanizable material,

said outer layer being applied inoverlapping segments, the lapped edges of said segments presenting outwardly projecting seams; placimg said ball to force said outer layer against the walls of said mold and to invert inwardly said seams;v

curing said ball in said mold; releasing said intemal pressure; and removing said ball from said mold.

2. A method of making an inflatable athletic ball, comprising: forming an inflatable rubber ball of smooth contour; applying an outer layer thereto comprising some vulcanizabie material, said outer layer being applied in overlapping segments, the lapped edges of said segments presenting outwardly projecting seams; placing said ball in a mold; applying internal pressure to said ball to force said outer layer against the walls of said mold and to invert inwardly said seams; curing said ball in said mold; releasing said internal pressure; removing. said ball from said mold; and applying a protective cover ,to said ball. a it 3. A methodof making an inflatable athletic ball, comprising: forming an unfinished hollow ball with inwardly projecting-seams; applying acover of vulcaniaablematerial to said ball; plac- 'with said. initially outwardly projecting seams now projecting inwardly; removing said ball from said first mold: applying a cover of vulcanizable material; placing said ball in a second mold; and applying internal pressure and vulcanizing heat to said ball to force the seams outwardly into thematerial of thecover and to per- .manentlyembed them therein;

5. A method of making an inflatable athletic ball, comprising: making. Va -form having the shape of the finished ball; applyingsa, layer of segments of sheeted material having a vulcanizable constituent to said form with adjacent segment edges lapped to present outwardly extending seams; placing the unfinished ball in a first mold of the shape of the. finished ball; ap-' plying internal pressure to said ball to force said layer of segments against the walls of said first mold; partially vulcanlzing said ball while it is subjected to said pressure whereby the exterior surface of said unfinishedball becomes smooth and the interior surface presents inwardly projecting seams; releasing said internal pressure; v

removing said ball from said first mold; applying a cover to said ball of uncured vulcanizable material; placing said ball in a, second and larger mold; applying internal pressure to said ball; and vulcanizing the vulcanizable materials while said pressure is maintained whereby said inwardly projecting seams are forced outwardly into the cover of vulcanizable material and fixsaid ball from said first mold; applying a vul-.

against the walls of said second mold and to l stretch said fabric wall and force said fabric wall outwardly against said rubber cover and to extrude the seams of said fabric wall outwardly and embed said seams in said rubber cover; vulcanizing said ball; removing some of the fluid from said bladder; and removing the finished ball from said second mold. a I

7. A method of making an inflatable athletic ,ball, comprising: forming an inflatable rubber bladder; inflating said bladder to a size slightly smaller than that of the finished ball; coating the exterior surface of said bladder with rubber cement; applying to said cement coated bladder a plurality of segments of rubberized fabric with lapped meeting edges to form an outer wall upon the bladder with outwardly projecting seams; partially vulcanizing the unfinished ball under pressure of additional inflation in a first mold of a size approximately that of said unfinished ball whereby said unfinished ball is caused to have a smooth exterior surface and inwardly projecting seams; deflating and removing said ball from said first mold; coating the outer surface of said fabric wall with rubber cement; applying an uncured rubber cover-to said cement coated fabric wall; vulcanizing said unfinished ball in a second mold of the size of the finished ball under pressureof additional inflation whereby said previously inwardly projecting seams are forced outwardly and permanently embedded in said rubber cover; and deflating and removing from said second mold the finished ball.

8. A method of making tan-inflatable athletic ball, comprising: forming an inflatable rubber bladder; inflating said bladder with liquid alco- 1101 in' a first mold to a size slightly smaller than that of the finished ball, said liquid alcohol having a liquefaction point above normal atmospheric temperatures but below the temperature of vulcanization; cooling said alcohol to a temperature below its liquefaction point and removing said bladder from said mold; coating the exterioi' surface of said bladder with rubber cement; applying to the cement coated bladder a plurality of segments of rubber fabric with lapped meeting edges to form an outer fabric wall upon said bladder with outwardly projecting seams; partially vulcanizing the unfinished ball under pressure of additional inflation in a second mold of a size approximately'that of the unfinished ball whereby the unfinished ball has a smooth exterior surface and inwardly projecting seams; deflating and removing said ball from said second mold; coating the outer surface of said fabric wall with rubber cement; applying an uncured rubber cover to the said cement coated fabric wall; vulcanizing the unfinished ball in a third mold of the size of th finished ball under pressure of additional inflation whereby said previously inwardly projecting seams are forced outwardly and permanently embedded in said rubber cover; and deflating and removing from said third mold the finished ball.

9. A method of making an inflatable athletic ball, comprising: making an inflatable central rubber form in the shape desired for the finished ball; inflating said form to a size slightly less than that of the finished ball; coating said form with rubber cement; applying a layer of segments of rubberized fabric material to said form a with the edges of each segment lapped with respect to the edges of adjacent segments to pre sent outwardly projecting seams; placing said form and fabric layer in a first mold of a size slightly less than that of the finished ball; additionally inflating said form as to increase the internal pressure and force said fabric segments into contact with the walls of said first mold and eliminate said outwardly projecting seams and form corresponding inwardly projecting seams; applying sufiicient heat for a sufficient time to partially vulcanize said form, said fabric material, and said cement; deflating said ball; remov ing said ball from said first mold; partially reinflating said ball; applying a coating of rubber cement to said ball; applying a layer of segments of rubber with butt joints to form a complete rubber cover for said ball; placing said ball in a second mold of the size of the finished ball; additionally inflating said ball to force the several elements of the ball outwardly toward the wall of said second mold, thereby eliminating said inwardly projecting seams and forming corresponding seams projecting outwardly into said rubber cover; vulcanizing said ball with heat; deflating said ball; and removing said ball from said second mold.

10. A method of making an inflatable athletic ball, comprisingzmaking a solid form of a material having a liquefaction point above normal atmospheric temperature but below the temperature of vulcanization, said form having the shape of the finished ball; forming a hollow ball-shaped wall on said form of which the material has a vulcanizable constituent; applying heat sufficient to raise said ball to the temperature of vulcanization and to liquefy said form material and maintaining said temperature a sufiicient time to vulcanize said constituent; and removing said liquid form material before said form material and ball are cooled from said temperature of vulcanization below the temperature of liquefaction of said form material.

11. A method of making an inflatable athleticball, comprising: making a solid form of a material having a liquefaction point below the temperature of vulcanization, said form having the shape of the finished ball; forming on said form while at a temperature below its point of liquevulcanizable material; placing said ball in amaterial having a vulcanizable constituent, said mold; applying internal pressure to said ball to force said outer layer against the walls of said mold and to stretch said fibrous material; curing {said ball-tin said mold while said fibrous material stretched;

g ball provided with, an an outer fibrous layer and removing said-ball from said mold.

14'. A method of making an inflatable athletic ball, comprising: forming an inflatable rubber inflating valve; applying thereto comprising'some vulcanizable material; placing said ball in a mold; applying internal pressure to said ball to force said outer layer against the walls of said mold and to place under tension said fibrous material;

curing said: ball in said mold while said fibrous material is under tension; releasing said internal pressure; removing said ballfrom said mold; and

applying a protective cover to said ball.

15. A method of'making an inflatable athletic h ball,.c0mprising: forming a hollow ball comprising fibrous and vulcanizable material and having van inflating valve; applying a cover of vulcanizable material to said ball; placing said ball in a mold; applying internal pressure to said ball and thereby placing said fibrous material under tension; and vulcanizing said cover on said ball while said fibrous material is under tension.

16-. A method of making an inflatable athletic ball, comprising: forming a hollow ball comprising some vulcanizable material and some fibrous material and provided with an inflating valve; placing said ball in a firstmold; applying internal pressure and heat to said ball to stretch said fibrous material and partially cure said ball while said fibrous material is under tension; removing said ball from said first mold; applying a cover of vulcanizablematerial; placing said ball in a second mold; and applying internal pressure and vulcanlzing heat to said ball to additionally stretch said fibrous material and complete. the curing of said ball whilesaid fibrous material is under tension. p

17. A method of making an inflatableathleti'c ball, comprising: making a form having the shape of the finished ball; applying a layer of fibrous material having a vulcanizable constitutent to said form; placing the ball in a first mold of the shape of the finished ball; applying internal pressure to said ball to force said layer of fibrous material against the walls of said first mold, and to place the said fibrous material under tension; partially vulcanizlng said vulcanizable constituent of said fibrous material of said ball while said ball is subjected to said pressure and said fibrous material is under tension; releasing said internal pressure; removing said ball from said first mold; applying a cover to said ball of uncured vulcanizable material; placing said ball in a second and larger mold; applying internal pressure .to said ball to place the said fibrous material under additional tension; and vulcanizing the vulcanizable releasing said internal pressure;-

materials of said ball while said pressure is 'maintained whereby said fibrous material is embedded in said vulcanizable materials and given a permanent set.

18. A method of making an inflatable athletic ball, comprising: forming an inflatable rubber bladder having a fluid valve; injecting fluid-into said bladder through said valve until the size of said bladder is slightly less than that of the finished ball; applying a vulcanizable cement to the outer surface of said bladder; applying a layer of rubberized fibrous material to said cement covered bladder, said fibrous material forming an intermediate wall of said ball; placing said ball in a first mold of a size slightly smaller than i that of the finished ball; injecting additional fiuid'into the bladder through said valve so as to force said intermediate wall of fibrous material against the inner face of said first mold and to place said fibrous material under tension; partially vulcanizing said ball while said fibrous material is under tension; removing fiuid from said bladder; removing said ball from said first mold; applying a vulcanizable cement to the outer surface of said fibrous wall; applying an uncured rubber cover to said cement covered ball; placing said ball in a second mold of the size of the finished ball; injecting additional fluid-into said bladder through said valve so as to force said rubber cover against the walls of said second mold and to further stretch said fibrous wall and force said fibrous wall outwardly against said rubber cover; vulcanizing said ball while said fibrous wall is under tension; removing some of the fluid from said bladder; and removing the finished ball from said second mold;

19. A method of making an inflatable athletic ball, comprising: forming an inflatable rubber bladder provided with an inflating valve; inflating said bladder to a size slightly smaller than that of the finished ball; coating the exterior surface of said bladder with rubber cement; applying to saidcement coated bladder a layer of rubberized fibrous material to form .an intermediate wall upon the bladder; placing the ball in a first mold slightly larger than said ball;

' additionally inflating said ball; vulcanizing said ball while inflated whereby said fibrous material "is vulcanized under fatigue; deflating and removing said ball from said first mold; coating the outer surface of said fabric wall with rubber cement; applying an uncured rubber cover to said cement coated fibrous wall; placing said ball in a second mold of the size of the finished ball; additionally inflating said ball whereby said fibrous material is additionally stretched; vulcanizing said ball whereby said fibrous material is vulcanized a second time under fatigue; anddeflating and removing from said secondmold the finished ball.

20. A method of making an inflatable athletic ball, comprising: making an inflatable central rubber form in the shape desired for the finished ball and provided with an inflating .valve; inflating said form to a size slightly less than that of the finished ball; coating said form with rubber cement; applying -a layer of rubberized fibrous material to said form; placing said form and fibrous layer in a first mold of a size slightly less'than that of the finished ball; additionally inflating said form so as to increase the internal pressure and force said fibrous material into contact with the walls of said first mold and stretch said fibrous material; applying sufilcient with butt joints to form a complete rubber cover,

for said ball; placing said ball in a second mold ot the size of the finished ball; additionally inflating said ball to force the several elements of the ball outwardly toward the wall or said second mold, thereby to further stretch said fibrous material; vulcanizing said ball with heat; deflating said ball; and removing said ball from said second 5 mold.

' WILLIAM J. VOIT. LII'I'H C. 

